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Ultrasound has long been known to be capable of measuring water level. Zero-degree ultrasound transducers may be used to send an L-wave through the fluid and receive a reflected signal from the fluid/gas interface surface. The level of the fluid is proportional to the sound wave time of flight to traverse the water path. This approach may even be used from outside the fluid containment wall by sending the wave through the tank or pipe bottom. The approach, however, does not work well if there is only a thin layer of fluid consisting of one or two millimeters or even only a few droplets. Surface waves are also known to be sensitive to the presence or absence of fluid on a surface. A surface wave may be transmitted a significant distance by a transmitting transducer and then received by a similar transducer. If the surface along the wave path is wet with even a few droplets of fluid, the surface wave may be significantly attenuated. Generating and measuring such a surface wave from the opposite side of a tank or pipe containment wall and separating the near-wall surface wave from the far-wall surface wave, however, is more challenging. The feasibility of an approach for producing a surface wave on the opposite side of a steel plate to sense the presence or absence of fluid is discussed. This approach is supported by 2-D finite element modeling of the measurement configuration and by empirical demonstration of the technique's sensitivity. This technique was developed for measurement of a very small amount of fluid that may condense within a used nuclear fuel canister after it cools for several years. Early detection of fluid would provide advance warning of potential degradation to internal components in time for mitigation or management of the waste inside that container. Other potential applications include non-intrusive detection of trace liquids within any sealed container, within inaccessible plena of aircrafts or within other inaccessible complex welded skin structures. [ABSTRACT FROM AUTHOR]

The challenges of modeling and simulation for Non Destructive Examination (NDE) research and development at AREVA NDE Solutions Technical Center (NETEC) are presented. In particular, the choice of a relevant software suite covering different applications and techniques and the process/scripting tools required for simulation and modeling are discussed. The software portfolio currently in use is then presented along with the limitations of the different software: CIVA for ultrasound (UT) methods, PZFlex for UT probes, Flux for eddy current (ET) probes and methods, plus Abaqus for multiphysics modeling. The finite element code, Abaqus is also considered as the future direction for many of our NDE modeling and simulation tasks. Some application examples are given on modeling of a piezoelectric acoustic phased array transducer and preliminary thermography configurations. [ABSTRACT FROM AUTHOR]